I'll have to admit to not seeing the foldable spare for 5 years now. It was November 2000 the last time I had it on a tour. And used it on the last day because the 1992 Cheng Shin 35mm tire, bought in Austria, blew off the rim three times. I decided the old, tough, reliable Cheng Shin had finally given up its soul. Or the 8.5 years of continous mounting and 7,000+ miles had finally weakened something. I store the Michelin HiLite Tour tire folded in its box. Michelin must have used some good quality sidewall material. I'll have to remember to pull the tire out of its box to see if its still in good shape. I have some Specialized Epic 41mm tires back from about the mid 1980s that are showing some sidewall hardening, brittleness.
I prefer the kevlar bead tire for a spare because it takes up much less room than a folded wire bead tire. Space in my panniers is at a premium. And the idea of hanging it on the outside goes against my bicycle neatness principles. I'm a slob in many things, but not bikes. Neat and sleek is right.